According to the Centers for Disease Control, Cryptosporidiosis, a water-borne disease caused by a parasite invisible to the human eye, affected more than 10,000 people in the U.S. in 2008. The parasite rests within the small intestines of people infected by the disease, where the subsequent symptoms can include stomach cramps, dehydration, nausea, vomiting, fever, weight loss and diarrhea.

The disease, also known as Crypto, is transmitted by ingesting the parasite, frequently found in illnesses contracted from recreational waters. It’s natural to assume that the chlorine-treated pool you choose to swim in will protect you from Crypto, but the Centers for Disease Control advises the parasite is resistant to chlorine and can survive in a pool long enough to infect you or your loved ones. In addition to following these CDC-recommended steps to protect you from Crypto, the CDC recognizes secondary pool disinfectant systems such as ozone sanitation as one of the most reliable ways to neutralize Crypto and help ensure you enjoy a healthy swim.